Heart Arrhythmia

Heart arrhythmia claims don't behave like most cardiac claims. In our analysis of 1,111 BVA cases, the grant rate is 36 percent, six points above the overall Board average. The remand rate is 39 percent, twelve points above average. And the connection type that drives the most grants isn't direct service connection. It's presumptive. For Vietnam-era veterans, the Agent Orange presumption under 38 CFR § 3.309(e)) covers ischemic heart disease, and many atrial fibrillation cases run through that pathway as secondary to a documented ischemic primary.

The data cuts against a few common assumptions. Veterans whose arrhythmia developed in their fifties or sixties often assume the long latency rules out service connection. The Vietnam-era data says otherwise. Veterans whose cardiologist diagnosed atrial fibrillation often assume the Agent Orange presumption doesn't apply because afib isn't on the presumptive list. That's literally true, but the presumption covers ischemic heart disease, and many arrhythmias develop secondary to it. The chain through DC 7005 (arteriosclerotic heart disease) as the presumptive primary, with DC 7010 (supraventricular arrhythmias) as the rated secondary, is the dominant winning pathway in the dataset.

The remand rate is the other story. C&P exams for arrhythmia are flagged inadequate 66 percent of the time, well above the 52 percent overall average. The examiner doesn't address episode frequency, which DC 7010 explicitly ties the rating to. The examiner doesn't review Holter monitor data. The examiner defaults to "more likely due to age-related cardiovascular disease" without engaging with the herbicide exposure history. The Board sends nearly two of every three cases back for a better workup. This page covers the rating ladder under 38 CFR § 4.104, the Agent Orange presumptive pathway, the nexus cliff, the C&P inadequacy pattern, and how to document episode frequency to anchor the rating tier.

TL;DR

• Heart arrhythmia claims grant at 35.5 percent across 1,111 BVA cases. Denied 25.9 percent (288), remanded 38.6 percent (429), one of the highest remand rates I track outside the respiratory cluster.
• Strong nexus grants at 89.2 percent. Weak nexus grants at 4.5 percent. Missing nexus grants at 8.0 percent. Same cliff that shows up across every condition.
• C&P exams are flagged inadequate 65.8 percent of the time for arrhythmia, well above the 52 percent overall average and a key driver of the high remand rate.
• Presumptive connection is the dominant path at 191 cases, including 230 cases citing herbicide exposure and 86 citing Agent Orange specifically. The Vietnam-era tilt is the structural story.
• DC 7010 (supraventricular arrhythmias) is the primary diagnostic code at 49 coded cases, with DC 7005 (arteriosclerotic heart disease) at 34 and DC 7101 (hypertension) at 22.
• Lay statements quoted in the decision are associated with a 42.5 percent grant rate versus 30.6 percent when not quoted, a 12-point spread, smaller than most conditions but still material.

1,111 Cases: The Cardiac Cluster at the Board

Heart arrhythmia is one of the larger single cardiac conditions in my BVA dataset. The 1,111 cases include atrial fibrillation, supraventricular tachycardia, ventricular arrhythmias, paroxysmal atrial flutter, and related rhythm disorders coded under the cardiovascular schedule at 38 CFR § 4.104.

The headline outcome split:

• Granted: 394 cases (35.5 percent)
• Denied: 288 cases (25.9 percent)
• Remanded: 429 cases (38.6 percent)

The 38.6 percent remand rate defines the practical experience of an arrhythmia claim at the BVA. More than one in three appeals goes back for additional development before the Board issues a merits decision. The remand portion is bigger than either grants or denials, which is unusual. The Board is sending cases back at an elevated rate because the files that arrive don't have what the Board needs to decide. The medicine is usually documented: the arrhythmia is on an EKG or a Holter monitor or a cardiology note. What's missing is the connection evidence, the C&P workup, or the rating detail that lets the Board reach a merits decision.

The 35.5 percent grant rate is still nearly five points above the overall BVA grant rate of 30.6 percent, a meaningful tilt in favor of arrhythmia claimants. But the path to that grant runs through a lot of remand churn.

The 38 Percent Remand Rate Tells the Whole Story

When I look at why arrhythmia cases remand more than they grant or deny, the pattern is consistent. The C&P examination doesn't address the specific rhythm disorder with enough specificity for the Board to assign a rating tier. The examiner notes "atrial fibrillation" without engaging with the documented episode frequency, the medications prescribed, the cardioversion history, or the ablation procedure dates. The rating decision picks a tier based on incomplete information. The veteran appeals. The Board finds the C&P inadequate to support the rating, and the case goes back for a supplemental examination or a new C&P entirely.

The C&P inadequacy rate is 65.8 percent for arrhythmia, well above the 52 percent overall average. The Board is finding nearly two of every three cardiac exams insufficient to decide on the rating.

What makes an arrhythmia C&P inadequate? The patterns repeat. The examiner doesn't address episode frequency, even though DC 7010 explicitly ties the rating tier to how many episodes per year. The examiner doesn't engage with the medication history: continuous antiarrhythmics like flecainide, sotalol, or amiodarone affect the rating analysis but get listed without explanation. The examiner skips procedural history (ablation procedures, cardioversions, pacemaker or ICD implantation). And for Vietnam-era veterans, the examiner often defaults to "more likely due to age-related cardiovascular disease" without engaging with the documented herbicide exposure history. The Board treats that kind of conclusory opinion as inadequate under the Barr v. Nicholson framework.

The remand rate for arrhythmia isn't a sign that the underlying claims are weak. It's a sign that the C&P workup most veterans receive isn't up to the standard the Board applies on appeal.

Agent Orange and Heart Disease: 38 CFR § 3.309(e)

The presumptive overlay is the part of arrhythmia claims most veterans miss until they're deep into the appeals process. In my dataset, the presumptive categories invoked:

• Herbicide exposure: 230 cases
• Agent Orange specifically: 86 cases
• Burn pit: 57 cases
• Gulf War: 53 cases

Herbicide and Agent Orange combined account for over 300 of the 1,111 cases in this subset, roughly 28 percent. That's a much larger presumptive footprint than most non-respiratory conditions get in my data.

The regulatory basis is 38 CFR § 3.309(e), which lists ischemic heart disease as a presumptive condition for veterans exposed to herbicide agents during qualifying service. The covered service includes Vietnam, certain inland waterways and offshore positions, Thailand military bases during specific windows, the Korean DMZ during specific windows, and several other categories codified in 38 CFR § 3.307.

Here's the part that catches arrhythmia claimants off-guard: ischemic heart disease is the presumptive condition, not atrial fibrillation specifically. The presumption covers coronary artery disease, myocardial infarction history, stable and unstable angina. Atrial fibrillation, supraventricular tachycardia, and other rhythm disorders are not on the presumptive list as standalone conditions.

But many arrhythmias develop secondary to underlying ischemic heart disease. A veteran whose atrial fibrillation arose in the context of documented coronary artery disease can pursue service connection for the arrhythmia as a secondary condition under 38 CFR § 3.310, with the primary ischemic heart disease established through the herbicide presumption. The Board has consistently granted these chains when the cardiology workup documents the relationship between ischemic disease and the arrhythmia.

This is why the 230 herbicide cases and 86 Agent Orange cases in my arrhythmia subset are higher than the 49 direct DC 7010 atrial fibrillation cases. Many arrhythmia claims aren't filed under direct service connection at all. They're filed as secondary to a herbicide-presumed ischemic heart disease primary, with the rhythm disorder as the rated downstream condition.

DC 7010 vs DC 7005: How the Board Picks

The diagnostic code structure under 38 CFR § 4.104 distinguishes among several cardiovascular conditions, and the code assigned affects both the rating ladder and the service connection analysis.

Code distribution in the arrhythmia subset

In my arrhythmia subset:

• DC 7010 (supraventricular arrhythmias): 49 cases
• DC 7005 (arteriosclerotic heart disease, coronary artery disease): 34 cases
• DC 7101 (hypertensive vascular disease): 22 cases

The presence of DC 7005 in the arrhythmia subset is the key data point. Cases coded under DC 7005 are typically cases where the primary cardiovascular finding is ischemic heart disease, with the arrhythmia as part of the overall clinical picture. These cases run through the Agent Orange presumption for Vietnam-era veterans, and they tend to grant at higher rates than direct-only arrhythmia claims. The DC 7010 cases are the cleaner arrhythmia diagnoses without an underlying ischemic finding. The DC 7101 cases reflect arrhythmia claims coded primarily under hypertensive vascular disease when chronic hypertension is the dominant finding.

DC 7010 tier definitions

The rating ladder under DC 7010 specifically:

• 10 percent: Permanent atrial fibrillation, or one to four episodes per year of paroxysmal atrial fibrillation or other supraventricular tachycardia documented by EKG or Holter monitor.
• 30 percent: More than four episodes per year documented by EKG or Holter monitor.

DC 7010 tops out at 30 percent. The higher cardiovascular tiers (60 percent and 100 percent) exist under different diagnostic codes, which since the 2021-11-14 rewrite of § 4.104 run on the General Rating Formula for Diseases of the Heart, a METs-only ladder. Ejection fraction and congestive heart failure were deleted as criteria and no longer appear anywhere in 38 CFR Part 4.

In my arrhythmia grant subset where a rating tier was coded:

• 10 percent: 36 cases
• 30 percent: 20 cases
• 60 percent: 21 cases
• 100 percent: 27 cases

The 100 percent tier shows up more often than the 60 percent or 30 percent tiers, which reflects the population of arrhythmia claimants whose case involves more than just a rhythm disorder: heart failure, or cor pulmonale and oxygen-dependent categories. Note that these cases were decided largely under the pre-2021 criteria, when a severely reduced ejection fraction was itself a route to 100 percent; that route no longer exists.

Strong Nexus Wins 89 Percent of the Time

The nexus-quality cross-tab for arrhythmia follows the same pattern that shows up everywhere else in my data, with the cliff just as steep.

• Strong nexus: 166 cases, 89.2 percent grant
• Adequate nexus: 205 cases, 78.0 percent grant
• Weak nexus: 313 cases, 4.5 percent grant
• Missing nexus: 162 cases, 8.0 percent grant
• Not applicable: 264 cases, 22.3 percent grant

The drop from adequate (78.0 percent) to weak (4.5 percent) is the canyon that defines most close cases. A veteran with a strong or adequate nexus opinion is in a fundamentally different position than a veteran with a weak or missing one. The Board treats those categories as nearly binary.

What makes a nexus strong for arrhythmia? The opinion engages with the specific arrhythmia diagnosis (atrial fibrillation, paroxysmal supraventricular tachycardia, ventricular ectopy) and walks through why that specific condition is at least as likely as not service-connected. It engages with the in-service evidence: EKG abnormalities documented during service, episodes of palpitations or chest pain in the service treatment records, cardiology consultations during active duty. It addresses alternative theories (hypertension, ischemic disease, sleep apnea, hyperthyroidism, electrolyte disturbances, alcohol use, age-related fibrosis) and explains why the in-service contribution is at least as likely as not the underlying or contributing cause. And it addresses the time course, drawing on the medical literature on long-latency cardiovascular effects of relevant exposures.

A nexus opinion that does all four of those things is what the Board characterizes as strong. A nexus opinion that hits one or two is adequate. A nexus opinion that hits none is weak or missing, and the case grants at 4.5 or 8.0 percent.

The Vietnam-Era Tilt

The Vietnam-era population is structurally over-represented in the arrhythmia subset because of the herbicide presumption. Vietnam-era veterans in 2026 are in their seventies and eighties on average. Cardiovascular disease prevalence in that age range is high regardless of military service. Many of these veterans developed arrhythmias decades after service, often in the context of broader cardiovascular disease that includes coronary artery disease, hypertension, and structural heart changes.

The Agent Orange presumption recognizes ischemic heart disease as service-connected for these veterans. When a cardiology workup documents both ischemic heart disease and arrhythmia, the arrhythmia can be claimed as secondary to the herbicide-presumed primary condition. The 230 herbicide cases and 86 Agent Orange cases in this subset are largely from this population.

The remand rate for Vietnam-era arrhythmia cases is high because the medical records span decades, the in-service evidence may be thin (service treatment records from 50 years ago are often incomplete), and the cardiology workup may need to address the relationship between several overlapping conditions. When they grant, the presumptive overlay does most of the heavy lifting for the service connection element, and the rating evidence, once developed, usually maps cleanly to DC 7010 or DC 7005.

For non-Vietnam-era veterans, the presumptive pathway looks different. Burn-pit-exposed veterans have a smaller body of presumptive precedent (57 cases). Gulf War veterans with arrhythmia have an even smaller body (53 cases). These cases generally run through direct service connection or secondary chains involving other service-connected conditions, without the same presumptive tailwind.

Inadequate C&P at 65.8 Percent

Across my full dataset, the C&P inadequacy rate is 52.0 percent. For arrhythmia, it's 65.8 percent. That's a 14-point tilt toward inadequacy specifically for this condition.

The patterns repeat. The examiner conducts a single-day evaluation and concludes the arrhythmia "appears stable" without engaging with the episode history over the past 12 months, even though DC 7010 explicitly ties the rating tier to documented episode frequency. The examiner doesn't review the Holter monitor data, which captures episode frequency over 24 or 48 hours. The examiner uses boilerplate opinion language without engaging with the veteran's specific exposure or service history. The examiner doesn't address comorbid conditions like sleep apnea, hypertension, or thyroid dysfunction that often drive arrhythmias.

When the Board flags an arrhythmia C&P as inadequate, the case usually goes back for a supplemental opinion or a new exam, not an outright grant. That's the structural reason the remand rate is 38.6 percent. The Board can't decide a rating on a record it considers insufficient. The practical implication is that the C&P workup is rarely the last word. A C&P that doesn't address episode frequency, medication history, ablation history, or comorbid conditions is one that can be challenged on appeal and very often is.

What I Can't Tell You From This Data

The 1,111 arrhythmia cases in my dataset are the cases that reached the BVA, not all arrhythmia claims filed with VA. The grant rate I'm reporting (35.5 percent) is the BVA grant rate. Many arrhythmia claims granted at the regional office under the Agent Orange presumption never appeal and aren't in this dataset.

The dataset codes connection type, nexus quality, and primary diagnostic code, but it doesn't reliably code episode frequency, METs on exercise testing, or other clinical metrics that drive rating decisions. (It also records ejection fraction inconsistently, which matters less than it once did: that criterion was removed from § 4.104 in 2021.) The dataset also doesn't distinguish arrhythmia subtypes consistently: paroxysmal atrial fibrillation, persistent atrial fibrillation, atrial flutter, AV nodal reentry tachycardia, and various ventricular arrhythmias may all show up under similar coding.

I can't tell you how much of the 230-case herbicide presumption volume is filed under direct DC 7010 versus secondary to a DC 7005 ischemic heart disease primary. The connection-type coding captures presumptive as the framework but doesn't always isolate whether the rating is on the arrhythmia itself or on the underlying ischemic disease. And the Board's coding of nexus quality is post-hoc; the 89.2-versus-4.5 spread is too large to be entirely coding noise, but some of it almost certainly is.

What the data can tell you is what the patterns look like at the Board, what the modal denial reasons are, and which structural variables move outcomes. It's a map of the terrain.

Three Action Items for Cardiac Claims

The 1,111 cases tell a fairly consistent story about what wins an arrhythmia claim.

One: examine the presumptive pathway before defaulting to direct connection. The 230 herbicide cases and 86 Agent Orange cases in the arrhythmia subset are larger than the 49 direct DC 7010 cases. For Vietnam-era veterans, the herbicide presumption covers ischemic heart disease, and arrhythmia secondary to a documented ischemic primary is a clinically defensible chain. The cardiology workup should establish the relationship between ischemic disease and the arrhythmia, and the claim should be filed with the presumptive primary as the anchor.

Two: invest in the C&P review and the supplemental medical opinion. The 65.8 percent C&P inadequacy rate is the structural reason the remand rate is 38.6 percent. Most veterans accept the C&P report as it comes. A private cardiology opinion that engages with episode frequency, medication history, comorbid conditions, and the specific service-connection theory is the document that turns a 35 percent grant rate into a 78 to 89 percent rate at adequate or strong nexus.

Three: document episode frequency directly. DC 7010 ties the rating to documented paroxysmal episodes per year. Holter monitoring, event monitor data, hospital admission records for cardioversion or rate control, emergency department visits for arrhythmia episodes, and a maintained patient log all contribute. The veteran whose file documents four or fewer episodes per year is at the 10 percent threshold. More than four episodes per year is the 30 percent threshold. Without the data, the rating defaults to the lower tier.

None of this is a guarantee. The 35.5 percent grant rate at the Board is the same 35.5 percent regardless of how clean any individual file is. But the structural variables that move outcomes are knowable and addressable.

The DC 7005 to DC 7010 Chain: Where Vietnam-Era Cases Actually Win

The winning Vietnam-era pattern usually starts with ischemic heart disease. DC 7005 covers arteriosclerotic heart disease and coronary artery disease, and ischemic heart disease is on the herbicide-presumptive list. The arrhythmia then becomes a secondary condition when the cardiology record connects the rhythm disorder to the ischemic primary.

That is different from filing atrial fibrillation as a standalone presumptive condition. Afib itself is not the presumptive disease. The stronger theory is often: herbicide exposure establishes ischemic heart disease, ischemic heart disease causes or aggravates the arrhythmia, and the arrhythmia is rated under the most accurate cardiovascular code.

The cardiology workup should document coronary artery disease, ischemia, myocardial infarction history, angina, stent or bypass history, METs, rhythm diagnosis, and the relationship between the ischemic condition and the arrhythmia. Without that bridge, the presumption may help the heart disease but leave the rhythm disorder exposed.

What to Get Your Cardiologist to Document for the Rating Tier

DC 7010 ties the rating to documented episodes per year. That means the file needs countable data: Holter monitor reports, event monitor data, EKGs, emergency department visits, cardioversion records, ablation history, medication changes, hospitalization for rate control, and the veteran's symptom log.

Four or fewer documented paroxysmal episodes usually points to the 10 percent tier. More than four documented episodes per year points to the 30 percent tier. If the broader diagnosis fits DC 7005, DC 7011, DC 7020, or another cardiovascular code, the higher tiers depend on the METs figure or implanted-device criteria rather than episode count alone.

Use an evidence checklist for cardiology opinions and track episodes and symptoms over time before asking for the opinion. A cardiologist cannot count episodes that the record never preserved.

When the C&P Exam Is Inadequate: Specific Things to Flag

Arrhythmia exams fail in predictable ways. The examiner does not address episode frequency. The examiner does not review Holter or event-monitor data. The examiner ignores cardioversion or ablation records. The examiner gives a generic age-related explanation without addressing herbicide exposure, ischemic disease, sleep apnea, hypertension, thyroid disease, or PTSD.

The pushback should name the missing piece. "The exam was inadequate" is weaker than "the examiner did not discuss the March Holter monitor showing six supraventricular tachycardia episodes, did not address the cardiologist's ischemic-heart-disease diagnosis, and did not explain why herbicide exposure was not relevant." Specific gaps are easier for VA or the Board to act on.

If the claim is secondary, the examiner also has to address causation and aggravation under 38 CFR § 3.310. A condition can be service-connected if the primary condition made it permanently worse, even if it did not cause the first episode.

Arrhythmia Secondary to Sleep Apnea, Hypertension, or PTSD

Not every arrhythmia claim is a Vietnam-era herbicide case. Sleep apnea drives arrhythmias in many veterans, especially when nocturnal hypoxia and untreated apnea are documented. Hypertension as a primary cardiac risk factor can support a secondary chain when structural heart changes or long-term blood pressure burden are in the record. PTSD secondary chains often include cardiac issues through sleep disruption, autonomic activation, medication effects, and stress physiology.

These claims need a real nexus opinion. The opinion should identify the arrhythmia subtype, the primary service-connected condition, the medical mechanism, the timeline, and competing causes. It should explain whether the primary condition caused the arrhythmia, aggravated it, or both.

Secondary condition pathways from heart conditions can help decide whether the strongest anchor is ischemic heart disease, sleep apnea, hypertension, PTSD, thyroid disease, kidney disease, or another diagnosed primary.

How DC 7010 Tops Out at 30 Percent, and Where the Higher Tiers Live

DC 7010 is limited. It tops out at 30 percent for more than four documented episodes per year. Veterans with severe cardiac impairment may need the file to show whether a different cardiovascular code better captures the condition.

DC 7005 for arteriosclerotic heart disease, DC 7011 for sustained ventricular arrhythmias, and DC 7020 for cardiomyopathy can reach 60 and 100 percent tiers when the METs or implanted-device criteria are met. The diagnosis has to fit. A rater should not force a case into DC 7010 if the medical picture is actually ischemic heart disease, cardiomyopathy, or sustained ventricular arrhythmia.

This is also where kidney disease and cardiovascular conditions overlap. Chronic kidney disease, hypertension, and cardiac impairment can compound each other, but each condition needs its own diagnostic and service-connection theory.

Bottom Line

Heart arrhythmia claims at the BVA grant at 35.5 percent across 1,111 cases, with a 38.6 percent remand rate elevated relative to most conditions. The rating ladder under 38 CFR § 4.104 distinguishes among DC 7010 for supraventricular arrhythmias (10 or 30 percent based on documented episode frequency), DC 7005 for arteriosclerotic heart disease (with higher tiers through cardiac function metrics), and DC 7101 for hypertensive vascular disease. The Agent Orange presumption under 38 CFR § 3.309(e) covers ischemic heart disease for veterans with qualifying herbicide exposure, and arrhythmia secondary to documented ischemic disease is the dominant presumptive pathway. In my dataset, 230 cases cite herbicide exposure and 86 cite Agent Orange specifically, more than the 49 direct DC 7010 cases. C&P exams are flagged inadequate 65.8 percent of the time for arrhythmia, well above the 52 percent overall average, which is the structural reason the remand rate runs so high. The nexus cliff is total: 89.2 percent grant rate at strong nexus versus 4.5 percent at weak nexus. The single most useful thing a veteran can do for an arrhythmia claim is examine the presumptive pathway, invest in a cardiology opinion that engages with the specific rhythm disorder and service-connection theory, and document episode frequency over the past 12 months directly.

Related Conditions

Heart arrhythmia claims commonly connect to hypertension, sleep apnea, PTSD, kidney disease, ischemic heart disease, and thyroid conditions. Veterans with episodic rhythm disorders should preserve monitor data and review the C&P exam prep tool before the cardiac exam.

Methodology and Limitations

• Data source: Outcome statistics, nexus-quality coding, denial-reason classification, C&P adequacy flags, connection-type tagging, diagnostic code distribution, and rating-tier coding are drawn from Claim Raven's analysis of 101,518 condition records drawn from 49,876 Board decisions, including 1,111 heart arrhythmia cases. Rating tier framework is drawn from 38 CFR § 4.104, primarily Diagnostic Code 7010 (supraventricular arrhythmias) and adjacent codes (7005 for arteriosclerotic heart disease, 7101 for hypertensive vascular disease). Presumptive framework is drawn from 38 CFR § 3.309(e) (herbicide exposure / Agent Orange: ischemic heart disease), 38 USC § 1116 (Agent Orange), 38 USC § 1119 (PACT Act burn pit), and 38 USC § 1117 (Gulf War undiagnosed illness). 2026 VA disability compensation rates referenced for context, with the 100 percent single veteran rate at $4,044.91 per month.
• Sample size: 1,111 BVA decisions involving heart arrhythmia, with outcomes split granted 35.5 percent (394 cases), denied 25.9 percent (288 cases), remanded 38.6 percent (429 cases). Sub-breakdowns by nexus quality, connection type, and presumptive category are drawn from the same subset, with sample sizes ranging from 7 cases (aggravation connection type) to 431 cases (direct connection type).
• Classification approach: Nexus quality (strong / adequate / weak / missing / not_applicable) is coded based on the Board's treatment of the medical opinion in each decision. Denial reason is the primary classified reason the Board names; secondary reasons are not captured in the primary denial-reason variable. Diagnostic code is the primary code discussed in the decision text; cases may discuss multiple codes in alternative.
• Limitations:
• The 1,111 arrhythmia cases are cases that reached the BVA, not all arrhythmia claims filed with VA. Claims granted at the regional office under the Agent Orange presumption without appeal aren't in this dataset.
• Arrhythmia subtype (paroxysmal atrial fibrillation, persistent atrial fibrillation, atrial flutter, supraventricular tachycardia, ventricular arrhythmias) is not consistently coded across decisions.
• Episode frequency, METs on exercise testing, and other clinical metrics that drive cardiovascular rating decisions are not coded as separate variables. Ejection fraction is likewise uncoded, and is no longer a rating criterion in any event after the 2021 amendment.
• The relationship between arrhythmia filed under direct DC 7010 and arrhythmia rated as secondary to a herbicide-presumed DC 7005 ischemic heart disease primary is not always clearly distinguished in the connection-type coding.
• Rating tier distribution among grants is based on the cases where a tier was clearly coded; not every grant has a clearly coded rating tier.
• Connection type and presumptive category invocation are coded based on the Board's discussion in the decision; cases may invoke multiple theories in alternative.
• The Agent Orange presumption analysis here reflects regulatory framework, not predictions of how any specific claim will be decided.
• Nexus quality is coded post-hoc by reviewing the decision text, and some hindsight bias is present.
• The Vietnam-era population is over-represented in the arrhythmia subset because the herbicide presumption brings these cases to the Board at elevated rates.
• These observations describe BVA patterns. They are not predictions of individual outcomes.